This invention concerns enhanced oil recovery making use of new surface-active agents.
Among the techniques used to improve the productivity of oil fields, the methods based on the use of chemical products are the object of numerous researches. These methods consist of injecting said chemical products in the field in a suitable form, through at least one injection well, of circulating them through the formation and of recovering the displaced hydrocarbons from at least one production well.
It is known that two main types of compounds may be injected in an oil formation: hydrosoluble polymers which have the object of decreasing the mobility of water; and surface-active substances acting by lowering the interfacial tension between the oil and the water so as to reduce the capillary forces which maintain the oil in the rock. These surface-active substances may be either ionic or non-ionic.
The development of enhanced recovery methods making use of chemical products is obviously dependent on the efficiency of said products, but also on economic factors and, among them, on the cost of the supplementary investments resulting from the application of the processes and from the cost of the products to be injected, the recovery of which can hardly be envisaged in the present state of the art.
An important object is thus to make efficient chemical products available at low cost for the exploitation of the fields.